1. Field of the Invention
The present invention relates to an external connection structure of an electric connection box for routing electric wires and, more particularly to a wiring part for collectively connecting a plurality of connector housings provided on electric wires or bundles of wires such as wiring harnesses to a connector housing provided in an electric connection box, or to a connector housing to be connected separately to an external wire bundle.
2. Description of the Prior Art
In wiring for electric devices in automobiles and the like, it sometimes becomes necessary to divide one bundle of wires into a plurality of bundles for separate electric connection, so that each of the bundles is connected to a connector housing, with a part of it being connected to a connector housing provided in an electric connection box, such as a junction box and a relay box, and the other connection housing is connected to a connection housing to be connected to an external wire bundle separately from the electric connection box. FIG. 4 shows an example of a conventional external connection structure of an electric connection box. In this drawing, numeral 1' indicates a junction box, and numeral 6' denotes a connector housing connected to a wiring which is constituted of a bus bar and as wiring board inside the junction box. Numerals 4' and 5' are connector housings connected to bundles of wire harnesses branched off from a bundle of wire harness; the connector housing 5' is connected to the connector housing 6', while the connector housing 4' is connected to a connector housing 8' separate from the junction box 1'. To this connector housing 8' is also connected a connection housing 7 branched off from the same wire harness. This is connected to a connector housing, which is not illustrated, provided below the junction box 1' in the drawing. The connector housings 8' and 4' are not included in the junction box 1' as stated above, but must be positioned near the junction box; and therefore it is called a through connector and fixedly mounted by a locking member on the side wall of the junction box.
In such an external connection structure of prior art, however, there is such a disadvantage that so many individual connections as the number of male and female connection housings are required and, in addition, the through connector is in most cases disposed in an unoccupied space in a motor vehicle. The through connector is sometimes not visible, which, therefore, will take much time in connecting the male and female connector housings and, besides, these connected state can not be confirmed.
Furthermore, there is also such a disadvantage that the through connector needs the selection of connector housings of different configurations in order to prevent incorrect insertion, and accordingly the terminal holding chamber of the connector housing often has much unused space, resulting in a poor space efficiency.